Substance use network characteristics and drug and alcohol use behaviors among young men who have sex with men (YMSM).

<bold>Background: </bold>Young men who have sex with men (YMSM) use alcohol and other drugs at rates higher than their heterosexual peers. While social networks of YMSM have been acknowledged as an important contextual influence on their health behavior, studies have largely focused on social and sexual networks rather than substance use networks, despite the potential importance of substance use alters in shaping substance use behavior.<bold>Method: </bold>Using data collected from a diverse sample of YMSM (n=156), two multilevel models examined the associations between network (e.g., degree and transitivity), dyadic (e.g., strength of relationship), and individual characteristics and two alter level dependent variables: recent drug use (versus no recent drug use) and frequency of substance use.<bold>Results: </bold>Results indicated that transitivity was associated with both recent drug use (OR=1.21, p=0.012) and more frequent substance use (b=0.08, p=0.002). Degree was not significantly associated with either variable. Furthermore, participants were also less likely to have recently used drugs (OR=0.93, p<0.001) and tended to use substances less frequently (b=-0.01, p=0.028) with older alters.<bold>Conclusions: </bold>Despite substantial interest in network influences on health, much remains unknown about the impact of network structures on substance use. The current findings suggest that structural characteristics of substance use networks may provide important information regarding the drug and alcohol use behavior of YMSM even when controlling for dyadic and individual characteristics. [ABSTRACT FROM AUTHOR]